Laundry method



July 23, 968 A. F. MARTZ. JR 3,393,970

LAUNDRY METHOD Original Filed Aug. 21, 1962 2 Sheets-Sheet 1 TIMER g5 SENSING j6 4g n CONTROL {0 0} H DETERGENT DISPENSER" 37 36 3 a6 :flfzfl I SENSING '7 N L M CELLS "t 1 7/ E m 58 0 u INCREASING 3 z SUPPLY WATER 5 HA RDNESS 4 22 g 3 A -23 D n m oprmun DETERGENT coucsnrmnon 453 X F V U SUPPLY WATER 5 68 62 HARDNESS arifiurfjyarfy fi; J, BY 6:? I J w 7 u m 7; DETERGENT comm/mow July 23, 1968 A. F. MARTZ. JR

LAUNDRY METHOD 2 Sheets-Sheet 2 Original Filed Aug. 21, 1962 umO .Lnodwnd cmv was mUQLlJLLUIl-I QQ M wu mo 502E .5150 mu @2350 5265 matic washing machine by reference to the conductivity 3,393,970 I v LAUNDRY METHOD 1, Arthur F. Martz, .Ir., Princeton, N.J., assignor to Whirlpool Corporation, a corporation of Delaware Original application Aug. 21, 1962, Ser. No. 218,247, now

Patent No. 3,223,108 dated Dec. 14, 1965.-Divided and ,i

this application Oct. 14, 1965, Ser. No. 496,020 I. r 9 Claims. (Cl. 8-,-137);.

ABSTRACT on THE DISCLOSURE A method of washing and rinsing clothes in an-autoinatic washing machine'wherein the electrical conductivity of the supply water, the washing-water, and the rinsing water are sensed to control automatically the operation of the washing machine.

Background of the invention This application is a division of my copending application Ser. No. 218,247, filed Aug. 21, 1962, now issued as US. Patent 3,223,108, on Dec. 14, 1965.

This invention relates to a method of washing and rinsing in an automatic washing machine as a fuction of the relative conductivities of the washing and rinsing liquids.

' Automatic washing machines in the past seve'ral'years have been designed with many automatic features directed toward improving the washing and rinsing'efiiciency and at the same time simplifying the operation thereof. A particularly difficult problem is'encountered, however,-'inattempting to automatically provide the dispensing detergent therein, as the optimum amount of detergent required is dependent upon the hardness of "It is, therefore, a feature ofthis invention to provide -a method of automatically controlling the addition and removal of detergent in awashing machine, whichcontrol is a function of the hardness of the water utilized Yet another of amethod of controlling the rinse cycle ofan autoof the detergent-free water provided thereto. It is a still further feature of this'invehtion' to profeatnre of the inventio'nis' the provision vide a method for automatically controlling the amount of detergent added to a washing machine as a function "of the hardness of thesupply'water and controlling the degree of rinse as a function of the conductivity of the laundry water. 'Other features and advantages will become apparent from the following detailed description'taken in connection with the accompanying drawings wherein:

FIGURE 1 shows a washing machine provided with a control embodying the invention;

FIGURE 2 is troli FIGURE 3 is a timer schedule illustrating the sequence of cam switch operation;

FIGURE 4 is a vertical sectionof a. sensing cell utilized in the control;

a schematic circuitdiagram of the con- 5 I 3,393,970 Patented July 23, 1963 ice FIGURE 5 is a graph showing optimum detergent concentrations for supply water of different hardness; and

FIGURE 6 is a graph showing percent detergent concentrations versus electrical resistance for supplywater of different hardnesses. a I In the illustrative embodiment of the invention disclosed in thedrawing, an automatic washer of generally conventional construction is shown to include a cabinet 10, a casing 11 and a clothes containing cylinder 12 mounted for rotary motion about a horizontal axis within the cabinet. A motor drive 14 drives a pulley 15 which rotates the cylinder 12 through a drive belt 16 and a drive pul ley 17. Associated with motor drive 14v is a spin solenoid 18 controlling the motor drive to vary .the speedof rotation of cylinder 12. p I p A pump 19 is coupled through a pipe20 to a sump 21 and a purge pump 22 is coupled through. a pipe23 to a, second sump 24. Pumps 19 and 22 serve to cycle the. laundry liquids to the washer and to remove the liquids at certain times in the operation of the machine. Purge pump 22 delivers liquid through a pipe 25 to a drain stand pipe 26. Pump 19 delivers the laundry liquid through a pipe 27 to a two-way valve 28 actuated by a solenoid 29 to route the laundry liquid either through a pipe 30 to the drain stand pipe 26 or through a pipe 31 through a first sensing device 32 to a spray nozzle 33 directin the liquid into the cylinder 12. A pipe 34 coupled to a source of supply water (not shown) is connected to a pair of solenoids 35 and 36 which control flow of the supply water through a pipe 37 to the washing machine and through a pipe 38 to a pair of sensing cells 39 and 40. The output of the sensing cells 39 and 40 is coupled through a pipe 41 to drain pipe 26, Control of the amount of laundry liquid in the machine is effected by an air pressure actuated water level switch 42 coupled through a pipe 43 to a pressure dome 44 open at its lower end to be actuated by the pressure of the laundry liquid in the washing machine. I.

. 3 The washing machine .is further provided with a detergent dispenser 45 including a motor 46 driving a feed screw 47 through an opening in the side of the washing machine to dispense detergent from the supply to the laundry liquid therein. A sensing control 48 and a timer 49 are provided to control the various steps of operation as hereinafter discussed.

The structure of each of the sensing cells 32, 39 and 40 is similar, the structure of cell 32 being shown in detail in FIGURE 4 to include an inlet port 50, outlet port 51, an enlarged central section 52 and a pair of spaced, opposed electrode plates 53 and. 54. The housing 55 is formed of an insulating material and maintains the electrode plates 53 and 54 electrically isolated from each other. When water is passed through the chamber 52 and a voltage is applied to the electrode plates 53 and 54 through a pair of leads 56 and 57, a current flows through the water, the magnitude of which is a function of the conductivity of the water, which is inversely proportional to the hardness of the water.

1 FIGURE 5 shows the optimum detergent concentration for washing fabric and the like in the washing machine, as a non-linear function of the resistance, and thus the harndess, of the supply water used. The resistance of the supply of water increases with a decreasing hardness of water, and thus less detergent is needed as the softnessof the water increases, as shown by line 58 of the graph.

FIGURE 6 graphically illustrates the non-linear relationship between the resistance of the rinse water and the percentage of detergent concentration in the rinse water for supply waters having different hardnesses as shown by the respective curves 60, 61, 62 and 63. A

vertical line 64 intersecting this family of curves indicates the preselected concentration of detergent in the laundry water which causes sensing device 32 to fire trigger device 101 and effectively terminate the rinse portion of the machine cycle. It can be seen that with soft water a different resistance is measured for a given percentage of detergent concentration in the diluted laundry water than with hard water.

FIGURE 2 shows the electrical circuitry of the timer 49 and the sensing control 48 of FIGURE 1. As shown, a timer motor 70 drives a series of cams A, B, C, D, E, F, G, H and I which actuate a series of switches 71 through 79 for supplying power from a pair of supply lines 80 and 81 to the electrical apparatus of the washing machine. conventionally, the supply may be a 60 cycle 115 volt supply. The control further includes a relay 82 actuating switch 83, a relay 84 actuating switches 85 and 86, and a relay' 87 actuating nor-mally closed switch 88 and normally open switch 89 of the control circuit.

Power is supplied to the control circuit 48 through a transformer 90 having a primary winding 91 and a pair of secondary windings 92 and 93. Th primary winding 91 has one end thereof connected to line 81 and the other end connected between the supply water sample valve 36 and switch 79 actuated by cam I so that when switch 79 is closed, current fiows through primary winding 91. Secondary winding 92 is connected across a bridge circuit including a resistor 94, a resistor 95, sensing units 32 and 40, and a resistor 96 in series with sensing unit 32. The output of the bridge circuit is coupled to an amplifier 97 whose output is fed through a rectifier 98 having a load resistor 99 connected in series with a resistor 100. A trigger device, which may be either a silicon control rectifier or a thyratron tube 101, but not limited thereto, receives an input signal from resistor 100 and switches to an on condition under predetermined voltage conditions across resistor 100 to actuate relay 84.

In addition, the secondary winding 93 of transformer 90 is connected to a series load circuit including a pair of resistors 102 and 103, and sensing device 39. The signal developed in this load circuit at a point 104 between resistor 103 and sensing device 39 is coupled through an amplifier 105, a rectifier 106, and a load resistor 107 to resistance 100.

FIGURE 3 shows the operation sequence of switches 71 through 79 controlled by the timer motor cams A through I. The darkened squares represent a closed condition of the switches and the light squares represent an opened condition of the switches in the respective ones of thirty different timer steps.

In using the washing machine, the operator, after having loaded the machine with the fabrics to be washed. initiates operation by actuating the timer 49 to its start position. The prewash cycle of steps 1 through 3 is provided to pre-soak the clothes for removing a portion of the loose dirt therefrom. During time interval 1, switches 71, 72, 73 and 75 are closed by the cams A, B, C and E. Power is applied thereby to the drive motor 14, solenoid 29, and fill valve 35 through the pressure switch 42 which is in its leftward position at this time. Supply water is delivered to the machine until it reaches the level 110 designated by the dashed line in FIGURE 1. This causes the pressure switch 42 to move to its rightward position whereby the fill valve solenoid 35 is de-energized. The motor 14 rotates container 12 and the clothes are prewashed. During interval 3 power is applied to time-r m otor 70 through normally closed switch 83. The spin and pump out cycle follows, occurring during time intervals 4 and during which switch 73 is opened by cam C, deenergizing the solenoid on the two-way valve 28 thereby allowing laundry water to be removed from the machine. Switch 74 is closed by cam D actuating the spin clutch solenoid 18. Basket 12 is rotated at a high speed and water is removed by the pump 19 through the de-energized 4 two-way valve 28 and pipe 30 to the drain stand pipe 26.

Time intervals 6 through 16 cover the wash period and include intervals 6 to 13 during which the conductivity of the water in the machine is sensed and the amount of detergent added to the wash water is controlled. As shown, switches 71, 72, 73, 75, 78 and 79 are closed by their associated cams during time interval 6. Concurrently, fill valve 35admits water to the washing machine, two? way valve 28 recycles the water through the machine, detergent dispenser motor 46 is actuated and detergent from dispenser 45 is fed via the feed screw 47 into the washing machine. The closing of switch 79 actuates the supply water sample valve 36 at this time to allow water to pass through sensing devices 39 and 40 and at the same time connects the primary of transformer 90 across lines and 81. Relay 87 is actuated as switch 78 is closed, switch 88 is opened and switch 89 is closed during this period. The sensing control is now conditioned to sense the conductivity of the supply water and the laundry water within the washing machine containing the delivered detergent.

The initial conductivity of the supply water sensed by sensing devices 32 and 40 produces a substantially equal resistance in the bridge circuit, since at the initial stage, substantially no detergent is present in the water in the hub. Resistance 96, in series with sensing device 32 unbalances the bridge circuit and aplication of the signal from secondary 92 to the points 111 and 112 of the bridge circuit causes an output to be developed in the bridge circuit between points 113 and 114. This signal is fed to amplifier 97 which in turn is coupled to rectifier 98 and a direct current is developed through resistors 99 and 100. At the same time transformer secondary 93 supplies a potential arcoss the series circuit including resistor 102, switch 89 and sensing device 39. As the conductivity of the supply water normally remains substantially constant during the wash cycle, a substantially constant signal is produced in this series circuit with a resulting constant potential at point 104. This signal is amplified through amplifier 105, and rectifier 106 develops a direct current in its load circuit including resistor 107 and 100. The currents developed by the two rectifiers have opposing directions of flow and the resulting low potential developed cross resistor 100 is below the trigger potential of device 101.

If the initial supply water is hard" it will have a high conductivity sensed by device 39 and the current developed by rectifier 106 will be high and of a substantially constant value. The resistance sensed by devices 32 and 40 is low and since resistor 96 is in the bridge circuit an output is developed between points 113 and 114. As detergent is added, the resistance sensed by device 32 decreases and the signal developed between points 113 and 114 of the bridge circuit is reduced in magnitude with the result that the current flow through resistor 99 is decreased. Since the two currents through resistor 100 are in opposition, the net effect is to increase the potential across resistance 100. When this potential reaches the triggering potential of trigger device 101, it is switched to the on condition and current flows through relay 84 opening switches and 86, thereby de-energizing the detergent dispensing motor 46.

During time interval 13, switch 76 closes and energizes timer motor 70. At the commencement of time interval 14, the switches 75, 78 and 79 are opened by their respective cams. The clothes container 12 continues to rotate, andwater is pumped via pump 19 through the nozzle 33 into the clothes and the washing cycle proceeds.

The pump out cycle occurs during period 17 in which switch 73 is opened by cam C and solenoid 29 is deenergized allowing the wash water to be removed from the sump 21 via pump 19, pipe 27, valve 28 and .pipe 30 to drain stand pipe 26. Commencing with time interval 18 switch 74 closes whereby spin clutch solenoid 18 is actuated to spin the clothes container 12 at a high speed removing excess wash water not drained during the pump out period. t t

The rinse cycle occupies time intervals 20, 21 and 22 during which the sensing control circuit is again activated to sense the conductivity of the supply water and the laundry water to reduce the detergent concentration within the laundry water by continuously diluting it with supply or rinse water until a predetermined level is reached. Switches 71, 72, 73, 75 and 79 are closed by their respective cams during the time interval 20. Fill valve 35 is actuated allowing supply or rinse water to enter the machine through pipe 37; two-way valve 29 is closed allowing the rinse water to be recycled by pump 19; the machine is drivenby the drive motor 14 and the supply water sample valve 36 is actuated. Since switch 78 is open, relay 87is 'de-energized closing switch 88 and opening switch 89. Thus, the sensing control circuit is conditioned to compare the conductivity of the supply water with the conductivity of the rinse water. Resistor 96 is now shorted out of the bridge circuit while resistor 103 is inserted in series with the secondary 93 and sensing device 39. The potential developed at point 104 is again a constant value and the current flow through resistance 107 is a constant value. Water is admitted into the washing machine via the fill valve, and the sensing devices 32 and 40 initially measure diffierent values of conductivity. Device 32 measures 'the conductivity of the rinse water containing detergent while device 40 measures that of the incoming supply water. Thus, a signal is developed between points 113 and 114 of the bridge circuit and there is developed a direct current through resistor 99 of a value proportional to the difference in the conductivities measured. If the supply water is soft or has a high resistance, this signal is large, but at the same time a relatively largesignal is developed atpoint 104 due to the high resistance measured by device 39 and the net result of the two currents flowing through resistor 100 in opposite directions is that an insufficient potential is developed to actuate trigger device 101. As the supply or rinse water continues to fill the Washing machine the conductivity of the laundry water in the machine changes, the resistance increases due to decreasing the percentage of detergent present and the conductivity measured by device 32 more nearly equals that measured by device 40 and the output signal between points 113 and 114 decreases. The net signal developed across resistance 100 increases, and when sufiicient rinse water has been added to reduce the detergent concentration to the desired level, trigger device 101 switches on actuating r'elay 84.

At the beginning of time interval 21 switches 76 and 77 are closed actuating the timer motor and purge pump 22. However, when the purge pump is energized, so is relay 82, and switch 83 is opened de-energizing the timer motor 70. Therefore, the timer motor 70 is de-energized during the entire operation of the purge pump, since differing amounts of laundry water must be removed from the machine due to different amounts of detergent being added to the laundry water during the wash portion of the cycle to reach the desired percentage of detergent concentration for a given water hardness. During interval 21, fill valve 35 supplies supply water to the machine faster than purge pump 22 can remove the diluted laundry water from sump 24. Therefore, purge pump 22 must remove laundry water from sump 24 until the laundry water reaches a level indicated by dashed line 115 in FIGURE 1 before the fill valve 35 will be energized by the action of switch 42 to its left-most position to dilute the laundry water, as shown in FIGURE 2. Fill valve 35 supplies water to the machine, when energized by switch 42, until the water level reaches a level indicated by the dashed line 110. Switch 42 will move to its rightmost position and fill valve 35 will be de-energized. However, at this point, timer motor 70 is not energized since relay 82 is holding switch 83 open. The aforementioned cycling or switch 42 continues until the trigger device 101 fires. Relay 82 is energized by triggerdevice 101 to it open switch 85 which de-energizes purge pump 22 and relay 82 which closes switch 83 to re-energize'timer motor 70-. During the time period 22 of the rinse-cycle, the purge pump is further deactivated by the opening'of-switch 77, as is the sensing control circuit.

The spin and pump out cycle occupiestime intervals 23 through 27 during which the drive motor 14 a'ndmain pump 19 are actuated as are the spin clutch solenoid18 and timer motor. Thus; the container 12 is rotated at a high speed and the water is removed from the washing machine. I

The last three time periods 28, 29 and 30 serve to'shu the machine down after the washing cycle has been completed.

, It is to be noted from the above description of operation of the automatic washing machine and sensing 'control circuit that device 39 provides a signal responsive to the conductivity of the supply water which is compared to a signal developed by the bridge circuit including devices 32 and 40. The combination of theoutputs of rectifiers 98 and 106 in resistor 100, which are proportional to the sensed conductivities, develops a voltage to trigger the device 101 dependent upon the hardness of the water and upon the amount of detergent added during the washing cycle or the detergent concentration in the rinse water during the rinse cycle.

It is to be observed further that the rinse operation is terminated at the same percent detergent concentration as shown by line 64, independent of the value of water hardness. This is due to the fact that the bridge output voltage across points 113 and 114, when measured or calculated at a resistance corresponding to the intersection of line 64 with curves 60, 61, 62, 63 and intermediate curves, is proportional to the voltage measured or calculated at point 104, with respect to neutral, which corresponds to points 65, 66, 67, 68 and intremediate points.

During the rinsing portion of the machine cycle when the difference between the bridge output voltage and the voltage at point 104 reaches a predetermined value, equal to the trigger value, device 101 triggersand the rinsing operation is terminated. Due to the aforementioned linear relationship and the fact that the voltage at 104 is proportional to the resistance at point 6.5-68 and that'the bridge output voltage is proportional to the resistance at points 60-63, the difference voltage will occur at different values of the bridge output voltage, but a constant percent detergent concentration as shown by line 64 in FIGURE 6.

During the washing portion of the machine cycle or during the detergent adding operation, the linear relationship between the voltage at point 104 and the resistance corresponding to points 65-68 is destroyed by the shorting resistor 103. Therefore, the curve of FIGURE 5 results so that optimum detergent is added, since the curve is the inverse of the optimum detergent versus water hardness curve.

While I have shown and described one embodiment of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and Scope of the invention as defined in the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. The method of washing and rinsing clothes in an automatic washing machine comprising the steps of: supplying detergent-free water to said machine; measuring the electrical conductivity of said detergent-free water; supplying detergent to said detergent-free water in the machine to obtain a laundry water; measuring the electrical conductivity of the water in the machine with the detergent added; starting a washing cycle when a predetermined relationship exists between the conductivity of said detergent-free water and said water with detergent added; supplying adition-al detergent-free water to said machine upon completion of the washing cycle to commence a rinse cycle; measuring the electrical conductivity of the water inthe machine as the additional detergent-free Water is added; and discontinuing the addition of said detergentfree water to said machine when the electrical conductvity of said laundry water reaches a predetermined relationship to the conductivity of the detergent-free water.

2. The method of washing and rinsing in an automatic Washing machine, comprising the steps of: supplying detergent-free water to said machine; measuring the electrical conductivity of said detergent-free water; supplying detergent to said detergent-free water in the machine to define laundry water therein; measuring the electrical conductivity of said laundry water in the machine; discontinuing supplying detergent when a predetermined relationship exists between the conductivity of said detergent-free water and said laundry water; initiating a washing cycle; supplying additional detergent-free water to said machine upon completion of the washing cycle to commence a rinse cycle; measuring the electrical conductivity of the laundry water in the machine as the additional detergentfree water is added thereto; and discontinuing the addition of said detergent-free water to said machine when the electrical conductivity of said laundry water reaches a predetermined relationship to the conductivity of the detergentfree water.

3. The method of rinsing clothes which have been washed in laundry water having detergent therein, comprising the steps of adding to the laundry water detergentfree water; measuring a physical condition of the laundry Water as the detergent-free water [is added thereto; and discontinuing the addition of said detergent-free water thereto when said physical condition of said laundry water reaches a predetermined relationship to the physical condition of the detergent-free water.

4. The method of claim 3 wherein said physical condition is an electrical conductivity condition.

5. The method of washing and rinsing in an automatic washing machine, comprising the steps of: providing detergent-free water; measuring a physical condition of said detergent-free water; dissolving detergent Iin said water to progressively vary the concentration of detergent in the water; measuring said physical condition of the water with said detergent dissolved therein; discontinuling the progressive variation of the concentration when a predetermined relationship exists between said measured physical condition of said detergent-free water and said water with said detergent dissolved therein thereby to provide a laundry water; initiating a washing cycle with said laundry water; terminating the washing cycle; supplying additional detergent-free water to said laundry water to form rinse water therefrom; measuring a physical condition of said rinse water as the additional detergent-free water is added thereto; and discontinuing the addition of said detergentfree water to said rinse water when said last-named physical condition of the rinse water reaches a predetermined relationship to said last-named physical condition of the detergent-free water.

6. The method of claim 5 wherein said first and lastnamed physical conditions are similar types of conditions.

7. The method of claim 5 wherein said first-named physical condition comprises the electrical conductivity of said detergent-free water.

8. The method of claim 5 wherein said last-named physical condition comprises the electrical conductivlity of said rinse water.

9. The method of washing and rinsing in an automatic washing machine, comprising the steps of: providing detergent-free water; measuring the electrical conductivity of said detergent-free water; adding detergent to said water to progressively increase the concentration of detergent in the water; measuring the electrical conductivity of the water with the detergent added thereto; discontinuing the addition of the detergent to the water when a predetermined relationship exists between the conductivity of said detergent-free water and said water With said detergent added thereto, thereby to provide a laundry water; initiating a washing cycle; terminating the washing cycle; supplying additional detergent-free water to said laundry water in the machine to form ninse water therefrom; measuring the electrical conductivity of said rinse water; and discontinuing the addition of said detergent-free water to said rinse water when the electrical conductivity of the rinse water reaches a predetermined relationship to the conductivity of the detergent-free water.

References Cited UNITED STATES PATENTS 3,086,836 4/1963 Ohman 9-137 3,160,317 12/1964 Hambro 8l37 FOREIGN PATENTS 231,717 12/1960 Australia.

LEON D. ROSDOL, Primary Examiner.

MAYER WEINBLATT, Assistant Examiner. 

